Establishing connections with chargers in multi-charger wireless power delivery environments

ABSTRACT

Techniques for establishing RF power connections with wireless power transmission systems in multi-wireless power transmission system environments are described herein. More specifically, the techniques describe a method for establishing a connection with an optimal wireless power transmission system when multiple wireless power transmission systems are within range.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 15/092,026 titled “ESTABLISHING CONNECTIONS WITH CHARGERS IN MULTI-CHARGER WIRELESS POWER DELIVERY ENVIRONMENTS” filed on Apr. 6, 2016, now allowed; which claims priority to and benefit from U.S. Provisional Patent Application No. 62/146,233 titled “SYSTEMS AND METHODS FOR WIRELESS CHARGING” filed on Apr. 10, 2015, both of which are expressly incorporated by reference herein.

TECHNICAL FIELD

The technology described herein relates generally to the field of wireless power transmission and, more specifically, to techniques for establishing wireless power radio frequency (RF) power connections with wireless power transmission systems (or chargers) in multi-wireless power transmission system environments.

BACKGROUND

Many portable electronic devices are powered by batteries. Rechargeable batteries are often used to avoid the cost of replacing conventional dry-cell batteries and to conserve precious resources. However, recharging batteries with conventional rechargeable battery chargers requires access to an alternating current (AC) power outlet, which is sometimes not available or not convenient. It is therefore desirable to derive power for mobile portable electronics via electromagnetic radiation. Some systems for wireless charging via electromagnetic radiation have been disclosed.

Some wireless power delivery environments include multiple wireless charging systems that are each capable of providing wireless power to wireless devices within range. In many cases, the wireless power delivery ranges of the wireless charging systems overlap resulting in more than one charger that is capable of providing a wireless device with power. In such cases, the multi-charger environments tend to result in unbalanced pairings between wireless devices and the wireless power transmission systems. That is, some wireless charging systems might be under-utilized while others provide power to a maximum number of allowable wireless devices.

Accordingly, a need exists for technology that overcomes the problem demonstrated above, as well as one that provides additional benefits. The examples provided herein of some prior or related systems and their associated limitations are intended to be illustrative and not exclusive. Other limitations of existing or prior systems will become apparent to those of skill in the art upon reading the following Detailed Description.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements.

FIG. 1 depicts a block diagram including an example wireless power delivery environment illustrating wireless power delivery from one or more wireless power transmission systems to various wireless devices within the wireless power delivery environment in accordance with some embodiments.

FIG. 2 depicts a sequence diagram illustrating example operations between a wireless power transmission system and a wireless receiver client for commencing wireless power delivery in accordance with some embodiments.

FIG. 3 depicts a block diagram illustrating example components of a wireless power transmission system in accordance with some embodiments.

FIG. 4 depicts a block diagram illustrating example components of a wireless power receiver client in accordance with some embodiments.

FIGS. 5A and 5B depict diagrams illustrating an example multipath wireless power delivery environment in accordance with some embodiments.

FIG. 6 illustrates an example wireless power delivery environment including multiple wireless power transmission systems and multiple power receiver clients in accordance with some embodiments.

FIG. 7 is a flow diagram illustrating an example process for establishing RF power connections with wireless power transmission systems in multi-wireless power transmission system environments in accordance with some embodiments.

FIG. 8 is a flow diagram illustrating an example process for determining whether to accept a connection invitation from a wireless power transmission system in accordance with some embodiments.

FIG. 9 is a flow diagram illustrating an example process of scoring wireless power transmission systems within range in accordance with some embodiments.

FIG. 10 is an example table illustrating various wireless power transmission system selection criteria in accordance with some embodiments.

FIG. 11 is a flow diagram illustrating another example process for establishing connections with continuous power delivery wireless charging systems in accordance with some embodiments.

FIG. 12 depicts a block diagram illustrating example components of a representative mobile device or tablet computer with one or more wireless power receiver clients in the form of a mobile (or smart) phone or tablet computer device in accordance with some embodiments.

FIG. 13 depicts a diagrammatic representation of a machine, in the example form, of a computer system within which a set of instructions, for causing the machine to perform any one or more of the methodologies discussed herein, may be executed.

DETAILED DESCRIPTION

Techniques for establishing RF power connections with wireless power transmission systems in multi-wireless power transmission system power delivery environments are described herein. More specifically, the techniques describe a method for establishing a connection with an optimal wireless power transmission system when multiple wireless power transmission systems are within range.

The following description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description. References to one or an embodiment in the present disclosure can be, but not necessarily are, references to the same embodiment; and, such references mean at least one of the embodiments.

Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but no other embodiments.

The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Certain terms that are used to describe the disclosure are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner regarding the description of the disclosure. For convenience, certain terms may be highlighted, for example using italics and/or quotation marks. The use of highlighting has no influence on the scope and meaning of a term; the scope and meaning of a term is the same, in the same context, whether or not it is highlighted. It will be appreciated that same thing can be said in more than one way.

Consequently, alternative language and synonyms may be used for any one or more of the terms discussed herein, nor is any special significance to be placed upon whether or not a term is elaborated or discussed herein. Synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification, including examples of any terms discussed herein, is illustrative only, and is not intended to further limit the scope and meaning of the disclosure or of any exemplified term. Likewise, the disclosure is not limited to various embodiments given in this specification.

Without intent to further limit the scope of the disclosure, examples of instruments, apparatus, methods and their related results according to the embodiments of the present disclosure are given below. Note that titles or subtitles may be used in the examples for convenience of a reader, which in no way should limit the scope of the disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the case of conflict, the present document, including definitions, will control.

I. Wireless Power Transmission System Overview/Architecture

FIG. 1 depicts a block diagram including an example wireless power delivery environment 100 illustrating wireless power delivery from one or more wireless power transmission systems (WPTS) 101 a-n (also referred to as “wireless power delivery systems”, “antenna array systems” and “wireless chargers”) to various wireless devices 102 a-n within the wireless power delivery environment 100, according to some embodiments. More specifically, FIG. 1 illustrates an example wireless power delivery environment 100 in which wireless power and/or data can be delivered to available wireless devices 102 a-102 n having one or more wireless power receiver clients 103 a-103 n (also referred to herein as “clients” and “wireless power receivers”). The wireless power receiver clients are configured to receive and process wireless power from one or more wireless power transmission systems 101 a-101 n. Components of an example wireless power receiver client 103 are shown and discussed in greater detail with reference to FIG. 4.

As shown in the example of FIG. 1, the wireless devices 102 a-102 n include mobile phone devices and a wireless game controller. However, the wireless devices 102 a-102 n can be any device or system that needs power and is capable of receiving wireless power via one or more integrated power receiver clients 103 a-103 n. As discussed herein, the one or more integrated power receiver clients receive and process power from one or more wireless power transmission systems 101 a-101 n and provide the power to the wireless devices 102 a-102 n (or internal batteries of the wireless devices) for operation thereof.

Each wireless power transmission system 101 can include multiple antennas 104 a-n, e.g., an antenna array including hundreds or thousands of antennas, which are capable of delivering wireless power to wireless devices 102. In some embodiments, the antennas are adaptively-phased radio frequency (RF) antennas. The wireless power transmission system 101 is capable of determining the appropriate phases with which to deliver a coherent power transmission signal to the power receiver clients 103. The array is configured to emit a signal (e.g., continuous wave or pulsed power transmission signal) from multiple antennas at a specific phase relative to each other. It is appreciated that use of the term “array” does not necessarily limit the antenna array to any specific array structure. That is, the antenna array does not need to be structured in a specific “array” form or geometry. Furthermore, as used herein he term “array” or “array system” may be used include related and peripheral circuitry for signal generation, reception and transmission, such as radios, digital logic and modems. In some embodiments, the wireless power transmission system 101 can have an embedded Wi-Fi hub for data communications via one or more antennas or transceivers.

The wireless devices 102 can include one or more receive power clients 103. As illustrated in the example of FIG. 1, power delivery antennas 104 a-104 n are shown. The power delivery antennas 104 a are configured to provide delivery of wireless radio frequency power in the wireless power delivery environment. In some embodiments, one or more of the power delivery antennas 104 a-104 n can alternatively or additionally be configured for data communications in addition to or in lieu of wireless power delivery. The one or more data communication antennas are configured to send data communications to and receive data communications from the power receiver clients 103 a-103 n and/or the wireless devices 102 a-102 n. In some embodiments, the data communication antennas can communicate via Bluetooth, Wi-Fi, ZigBee, etc. Other data communication protocols are also possible.

Each power receiver client 103 a-103 n includes one or more antennas (not shown) for receiving signals from the wireless power transmission systems 101 a-101 n. Likewise, each wireless power transmission system 101 a-101 n includes an antenna array having one or more antennas and/or sets of antennas capable of emitting continuous wave or discrete (pulse) signals at specific phases relative to each other. As discussed above, each the wireless power transmission systems 101 a-101 n is capable of determining the appropriate phases for delivering the coherent signals to the power receiver clients 102 a-102 n. For example, in some embodiments, coherent signals can be determined by computing the complex conjugate of a received beacon (or calibration) signal at each antenna of the array such that the coherent signal is phased for delivering power to the particular power receiver client that transmitted the beacon (or calibration) signal.

Although not illustrated, each component of the environment, e.g., wireless device, wireless power transmission system, etc., can include control and synchronization mechanisms, e.g., a data communication synchronization module. The wireless power transmission systems 101 a-101 n can be connected to a power source such as, for example, a power outlet or source connecting the wireless power transmission systems to a standard or primary alternating current (AC) power supply in a building. Alternatively, or additionally, one or more of the wireless power transmission systems 101 a-101 n can be powered by a battery or via other mechanisms, e.g., solar cells, etc.

The power receiver clients 102 a-102 n and/or the wireless power transmission systems 101 a-101 n are configured to operate in a multipath wireless power delivery environment. That is, the power receiver clients 102 a-102 n and the wireless power transmission systems 101 a-101 n are configured to utilize reflective objects 106 such as, for example, walls or other RF reflective obstructions within range to transmit beacon (or calibration) signals and/or receive wireless power and/or data within the wireless power delivery environment. The reflective objects 106 can be utilized for multi-directional signal communication regardless of whether a blocking object is in the line of sight between the wireless power transmission system and the power receiver client.

As described herein, each wireless device 102 a-102 n can be any system and/or device, and/or any combination of devices/systems that can establish a connection with another device, a server and/or other systems within the example environment 100. In some embodiments, the wireless devices 102 a-102 n include displays or other output functionalities to present data to a user and/or input functionalities to receive data from the user. By way of example, a wireless device 102 can be, but is not limited to, a video game controller, a server desktop, a desktop computer, a computer cluster, a mobile computing device such as a notebook, a laptop computer, a handheld computer, a mobile phone, a smart phone, a PDA, a Blackberry device, a Treo, and/or an iPhone, etc. By way of example and not limitation, the wireless device 102 can also be any wearable device such as watches, necklaces, rings or even devices embedded on or within the customer. Other examples of a wireless device 102 include, but are not limited to, safety sensors (e.g., fire or carbon monoxide), electric toothbrushes, electronic door lock/handles, electric light switch controller, electric shavers, etc.

Although not illustrated in the example of FIG. 1, the wireless power transmission system 101 and the power receiver clients 103 a-103 n can each include a data communication module for communication via a data channel. Alternatively, or additionally, the power receiver clients 103 a-103 n can direct the wireless devices 102.1-102.n to communicate with the wireless power transmission system via existing data communications modules. In some embodiments the beacon signal, which is primarily referred to herein as a continuous waveform, can alternatively or additionally take the form of a modulated signal.

FIG. 2 is a sequence diagram 200 illustrating example operations between a wireless power delivery system (e.g., WPTS 101) and a wireless power receiver client (e.g., wireless power receiver client 103) for establishing wireless power delivery in a multipath wireless power delivery, according to an embodiment. Initially, communication is established between the wireless power transmission system 101 and the power receiver client 103. The initial communication can be, for example, a data communication link that is established via one or more antennas 104 of the wireless power transmission system 101. As discussed, in some embodiments, one or more of the antennas 104 a-104 n can be data antennas, wireless power transmission antennas, or dual-purpose data/power antennas. Various information can be exchanged between the wireless power transmission system 101 and the wireless power receiver client 103 over this data communication channel. For example, wireless power signaling can be time sliced among various clients in a wireless power delivery environment. In such cases, the wireless power transmission system 101 can send beacon schedule information, e.g., Beacon Beat Schedule (BBS) cycle, power cycle information, etc., so that the wireless power receiver client 103 knows when to transmit (broadcast) its beacon signals and when to listen for power, etc.

Continuing with the example of FIG. 2, the wireless power transmission system 101 selects one or more wireless power receiver clients for receiving power and sends the beacon schedule information to the select power receiver clients 103. The wireless power transmission system 101 can also send power transmission scheduling information so that the power receiver client 103 knows when to expect (e.g., a window of time) wireless power from the wireless power transmission system. The power receiver client 103 then generates a beacon (or calibration) signal and broadcasts the beacon during an assigned beacon transmission window (or time slice) indicated by the beacon schedule information, e.g., Beacon Beat Schedule (BBS) cycle. As discussed herein, the wireless power receiver client 103 include one or more antennas (or transceivers) which have a radiation and reception pattern in three-dimensional space proximate to the wireless device 102 in which the power receiver client 103 is embedded.

The wireless power transmission system 101 receives the beacon from the power receiver client 103 and detects and/or otherwise measures the phase (or direction) from which the beacon signal is received at multiple antennas. The wireless power transmission system 101 then delivers wireless power to the power receiver client 103 from the multiple antennas 103 based on the detected or measured phase (or direction) of the received beacon at each of the corresponding antennas. In some embodiments, the wireless power transmission system 101 determines the complex conjugate of the measured phase of the beacon and uses the complex conjugate to determine a transmit phase that configures the antennas for delivering and/or otherwise directing wireless power to the power receiver client 103 via the same path over which the beacon signal was received from the power receiver client 103.

In some embodiments, the wireless power transmission system 101 includes many antennas; one or more of which are used to deliver power to the power receiver client 103. The wireless power transmission system 101 can detect and/or otherwise determine or measure phases at which the beacon signals are received at each antenna. The large number of antennas may result in different phases of the beacon signal being received at each antenna of the wireless power transmission system 101. As discussed above, the wireless power transmission system 101 can determine the complex conjugate of the beacon signals received at each antenna. Using the complex conjugates, one or more antennas may emit a signal that takes into account the effects of the large number of antennas in the wireless power transmission system 101. In other words, the wireless power transmission system 101 can emit a wireless power transmission signal from the one or more antennas in such a way as to create an aggregate signal from the one or more of the antennas that approximately recreates the waveform of the beacon in the opposite direction. Said another way, the wireless power transmission system 101 can deliver wireless RF power to the client device via the same paths over which the beacon signal is received at the wireless power transmission system 101. These paths can utilize reflective objects 106 within the environment. Additionally, the wireless power transmission signals can be simultaneously transmitted from the wireless power transmission system 101 such that the wireless power transmission signals collectively match the antenna radiation and reception pattern of the client device in a three-dimensional (3D) space proximate to the client device.

As shown, the beacon (or calibration) signals can be periodically transmitted by power receiver clients 103 within the power delivery environment according to, for example, the BBS, so that the wireless power transmission system 101 can maintain knowledge and/or otherwise track the location of the power receiver clients 103 in the wireless power delivery environment. Furthermore, as discussed herein, wireless power can be delivered in power cycles defined by power schedule information. A more detailed example of the signaling required to commence wireless power delivery is described now with reference to FIG. 3.

FIG. 3 is a block diagram illustrating example components of a wireless power transmission system 300, in accordance with an embodiment. As illustrated in the example of FIG. 3, the wireless charger 300 includes a master bus controller (MBC) board and multiple mezzanine boards that collectively comprise the antenna array. The MBC includes control logic 310, an external data interface (I/F) 315, an external power interface (I/F) 320, a communication block 330 and proxy 340. The mezzanine (or antenna array boards 350) each include multiple antennas 360 a-360 n. Some or all of the components can be omitted in some embodiments. Additional components are also possible.

The control logic 310 is configured to provide control and intelligence to the array components. The control logic 310 may comprise one or more processors, FPGAs, memory units, etc., and direct and control the various data and power communications. The communication block 330 can direct data communications on a data carrier frequency, such as the base signal clock for clock synchronization. The data communications can be Bluetooth, Wi-Fi, ZigBee, etc., including combinations or variations thereof. Likewise, the proxy 340 can communicate with clients via data communications as discussed herein. The data communications can be Bluetooth, Wi-Fi, ZigBee, etc.

In some embodiments, the control logic 310 can also facilitate and/or otherwise enable data aggregation for Internet of Things (IoT) devices. In some embodiments, wireless power receiver clients can access, track and/or otherwise obtain IoT information about the device in which the wireless power receiver client is embedded and provide that IoT information to the wireless power transmission system 300 over a data connection. This IoT information can be provided to via an external data interface 315 to a central or cloud-based system (not shown) where the data can be aggregated, processed, etc. For example, the central system can process the data to identify various trends across geographies, wireless power transmission systems, environments, devices, etc. In some embodiments, the aggregated data and or the trend data can be used to improve operation of the devices via remote updates, etc. Alternatively, or additionally, in some embodiments, the aggregated data can be provided to third party data consumers. In this manner, the wireless power transmission system acts as a Gateway or Enabler for the IoTs. By way of example and not limitation, the IoT information can include capabilities of the device in which the wireless power receiver client is embedded, usage information of the device, power levels of the device, information obtained by the device or the wireless power receiver client itself, e.g., via sensors, etc.

The external power interface 320 is configured to receive external power and provide the power to various components. In some embodiments, the external power interface 320 may be configured to receive a standard external 24 Volt power supply. Alternative configurations are also possible.

An example of a system power cycle is now described. In this example, the master bus controller (MBC), which controls the wireless power transmission system, first receives power from a power source and is activated. The MBC then activates the proxy antenna elements on the wireless power transmission system and the proxy antenna elements enter a default “discovery” mode to identify available wireless receiver clients within range of the wireless power transmission system. When a client is found, the antenna elements on the wireless power transmission system power on, enumerate, and (optionally) calibrate.

The MBC then generates beacon transmission scheduling information and power transmission scheduling information during a scheduling process. The scheduling process includes selection of power receiver clients. For example, the MBC can select power receiver clients for power transmission and generate a Beacon Beat Schedule (BBS) cycle and a Power Schedule (PS) for the selected wireless power receiver clients. As discussed herein, the power receiver clients can be selected based on their corresponding properties and/or requirements.

In some embodiments, the MBC can also identify and/or otherwise select available clients that will have their status queried in the Client Query Table (CQT). Clients that are placed in the CQT are those on “standby”, e.g., not receiving a charge. The BBS and PS are calculated based on vital information about the clients such as, for example, battery status, current activity/usage, how much longer the client has until it runs out of power, priority in terms of usage, etc.

The Proxy AE broadcasts the BBS to all clients. As discussed herein, the BBS indicates when each client should send a beacon. Likewise, the PS indicates when and to which clients the array should send power to and when clients should listen for wireless power. Each client starts broadcasting its beacon and receiving power from the array per the BBS and PS. The Proxy can concurrently query the Client Query Table to check the status of other available clients. In some embodiments, a client can only exist in the BBS or the CQT (e.g., waitlist), but not in both. A limited number of clients can be served on the BBS and PS (e.g., 32). Likewise, the CQT may also be limited to a number of clients (e.g., 32). Thus, for example, if more than 64 clients are within range of the wireless power transmission system, some of those clients would not be active in either the BBS or CQT. The information collected in the previous step continuously and/or periodically updates the BBS cycle and/or the PS.

FIG. 4 is a block diagram illustrating example components of a wireless power receiver client, in accordance with some embodiments. As illustrated in the example of FIG. 4, the receiver 400 includes control logic 410, battery 420, an IoT control module 425, communication block 430 and associated antenna 470, power meter 440, rectifier 450, a combiner 455, beacon signal generator 460, beacon coding unit 462 and an associated antenna 480, and switch 465 connecting the rectifier 450 or the beacon signal generator 460 to one or more associated antennas 490 a-n. Some or all of the components can be omitted in some embodiments. For example, in some embodiments, the wireless power receiver client does not include its own antennas but instead utilizes and/or otherwise shares one or more antennas (e.g., Wi-Fi antenna) of the wireless device in which the wireless power receiver client is embedded. Moreover, in some embodiments, the wireless power receiver client may include a single antenna that provides data transmission functionality as well as power/data reception functionality. Additional components are also possible.

A combiner 455 receives and combines the received power transmission signals from the power transmitter in the event that the receiver 400 has more than one antenna. The combiner can be any combiner or divider circuit that is configured to achieve isolation between the output ports while maintaining a matched condition. For example, the combiner 455 can be a Wilkinson Power Divider circuit. The rectifier 450 receives the combined power transmission signal from the combiner 455, if present, which is fed through the power meter 440 to the battery 420 for charging. The power meter 440 can measure the received power signal strength and provides the control logic 410 with this measurement.

The control logic 410 can receive the battery power level from the battery 420 itself. The control logic 410 may also transmit/receive via the communication block 430 a data signal on a data carrier frequency, such as the base signal clock for clock synchronization. The beacon signal generator 460 generates the beacon signal, or calibration signal, transmits the beacon signal using either the antenna 480 or 490 after the beacon signal is encoded.

It may be noted that, although the battery 420 is shown for as charged by and providing power to the receiver 400, the receiver may also receive its power directly from the rectifier 450. This may be in addition to the rectifier 450 providing charging current to the battery 420, or in lieu of providing charging. Also, it may be noted that the use of multiple antennas is one example of implementation and the structure may be reduced to one shared antenna.

In some embodiments, the control logic 410 and/or the IoT control module 425 can communicate with and/or otherwise derive IoT information from the device in which the wireless power receiver client 400 is embedded. Although not shown, in some embodiments, the wireless power receiver client 400 can have one or more data connections (wired or wireless) with the device in which the wireless power receiver client 400 is embedded over which IoT information can be obtained. Alternatively, or additionally, IoT information can be determined and/or inferred by the wireless power receiver client 400, e.g., via one or more sensors. As discussed above, the IoT information can include, but is not limited to, information about the capabilities of the device in which the wireless power receiver client is embedded, usage information of the device in which the wireless power receiver client is embedded, power levels of the battery or batteries of the device in which the wireless power receiver client is embedded, and/or information obtained or inferred by the device in which the wireless power receiver client is embedded or the wireless power receiver client itself, e.g., via sensors, etc.

In some embodiments, a client identifier (ID) module 415 stores a client ID that can uniquely identify the power receiver client in a wireless power delivery environment. For example, the ID can be transmitted to one or more wireless power transmission systems when communication is established. In some embodiments, power receiver clients may also be able to receive and identify other power receiver clients in a wireless power delivery environment based on the client ID.

An optional motion sensor 495 can detect motion and signal the control logic 410 to act accordingly. For example, when a device is receiving power at high frequencies, e.g., above 500 MHz, its location may become a hotspot of (incoming) radiation. Thus, when the device is on a person, e.g., embedded in a mobile device, the level of radiation may exceed acceptable radiation levels set by the Federal Communications Commission (FCC) or other medical/industrial authorities. To avoid any potential radiation issue, the device may integrate motion detection mechanisms such as accelerometers or equivalent mechanisms. Once the device detects that it is in motion, it may be assumed that it is being handled by a user, and would trigger a signal to the array either to stop transmitting power to it, or to lower the received power to an acceptable fraction of the power. In cases where the device is used in a moving environment like a car, train or plane, the power might only be transmitted intermittently or at a reduced level unless the device is close to losing all available power.

FIGS. 5A and 5B depict diagrams illustrating an example multipath wireless power delivery environment 500, according to some embodiments. The multipath wireless power delivery environment 500 includes a user operating a wireless device 502 including one or more wireless power receiver clients 503. The wireless device 502 and the one or more wireless power receiver clients 503 can be wireless device 102 of FIG. 1 and wireless power receiver client 103 of FIG. 1 or wireless power receiver client 400 of FIG. 4, respectively, although alternative configurations are possible. Likewise, wireless power transmission system 501 can be wireless power transmission system 101 FIG. 1 or wireless power transmission system 300 of FIG. 3, although alternative configurations are possible. The multipath wireless power delivery environment 500 includes reflective objects 506 and various absorptive objects, e.g., users, or humans, furniture, etc.

Wireless device 502 includes one or more antennas (or transceivers) that have a radiation and reception pattern 510 in three-dimensional space proximate to the wireless device 102. The one or more antennas (or transceivers) can be wholly or partially included as part of the wireless device 102 and/or the wireless power receiver client (not shown). For example, in some embodiments one or more antennas, e.g., Wi-Fi, Bluetooth, etc. of the wireless device 502 can be utilized and/or otherwise shared for wireless power reception. As shown in the example of FIGS. 5A and 5B, the radiation and reception pattern 510 comprises a lobe pattern with a primary lobe and multiple side lobes. Other patterns are also possible.

The wireless device 502 transmits a beacon (or calibration) signal over multiple paths to the wireless power transmission system 501. As discussed herein, the wireless device 502 transmits the beacon in the direction of the radiation and reception pattern 510 such that the strength of the received beacon signal by the wireless power transmission system, e.g., RSSI, depends on the radiation and reception pattern 510. For example, beacon signals are not transmitted where there are nulls in the radiation and reception pattern 510 and beacon signals are the strongest at the peaks in the radiation and reception pattern 510, e.g., peak of the primary lobe. As shown in the example of FIG. 5A, the wireless device 502 transmits beacon signals over five paths P1-P5. Paths P4 and P5 are blocked by reflective and/or absorptive object 506. The wireless power transmission system 501 receives beacon signals of increasing strengths via paths P1-P3. The bolder lines indicate stronger signals. In some embodiments the beacon signals are directionally transmitted in this manner to, for example, avoid unnecessary RF energy exposure to the user.

A fundamental property of antennas is that the receiving pattern (sensitivity as a function of direction) of an antenna when used for receiving is identical to the far-field radiation pattern of the antenna when used for transmitting. This is a consequence of the reciprocity theorem in electromagnetics. As shown in the example of FIGS. 5A and 5B, the radiation and reception pattern 510 is a three-dimensional lobe shape. However, the radiation and reception pattern 510 can be any number of shapes depending on the type or types, e.g., horn antennas, simple vertical antenna, etc. used in the antenna design. For example, the radiation and reception pattern 510 can comprise various directive patterns. Any number of different antenna radiation and reception patterns are possible for each of multiple client devices in a wireless power delivery environment.

Referring again to FIG. 5A, the wireless power transmission system 501 receives the beacon (or calibration) signal via multiple paths P1-P3 at multiple antennas or transceivers. As shown, paths P2 and P3 are direct line of sight paths while path P1 is a non-line of sight path. Once the beacon (or calibration) signal is received by the wireless power transmission system 501, the power transmission system 501 processes the beacon (or calibration) signal to determine one or more receive characteristics of the beacon signal at each of the multiple antennas. For example, among other operations, the wireless power transmission system 501 can measure the phases at which the beacon signal is received at each of the multiple antennas or transceivers.

The wireless power transmission system 501 processes the one or more receive characteristics of the beacon signal at each of the multiple antennas to determine or measure one or more wireless power transmit characteristics for each of the multiple RF transceivers based on the one or more receive characteristics of the beacon (or calibration) signal as measured at the corresponding antenna or transceiver. By way of example and not limitation, the wireless power transmit characteristics can include phase settings for each antenna or transceiver, transmission power settings, etc.

As discussed herein, the wireless power transmission system 501 determines the wireless power transmit characteristics such that, once the antennas or transceivers are configured, the multiple antennas or transceivers are operable to transit a wireless power signal that matches the client radiation and reception pattern in the three-dimensional space proximate to the client device. FIG. 5B illustrates the wireless power transmission system 501 transmitting wireless power via paths P1-P3 to the wireless device 502. Advantageously, as discussed herein, the wireless power signal matches the client radiation and reception pattern 510 in the three-dimensional space proximate to the client device. Said another way, the wireless power transmission system will transmit the wireless power signals in the direction in which the wireless power receiver has maximum gain, e.g., will receive the most wireless power. As a result, no signals are sent in directions in which the wireless power receiver cannot receiver, e.g., nulls and blockages. In some embodiments, the wireless power transmission system 501 measures the RSSI of the received beacon signal and if the beacon is less than a threshold value, the wireless power transmission system will not send wireless power over that path.

The three paths shown in the example of FIGS. 5A and 5B are illustrated for simplicity, it is appreciated that any number of paths can be utilized for transmitting power to the wireless device 502 depending on, among other factors, reflective and absorptive objects in the wireless power delivery environment.

II. Establishing Connections with WPTSs in Multi-WPTS Environments

As discussed herein, wireless power receiver clients can be simultaneously within range of multiple wireless power transmission systems in a wireless power delivery environment. The techniques discussed herein describe techniques for establishing connections with wireless power transmission systems in multi-wireless power transmission system environments.

FIG. 6 illustrates an example wireless power delivery environment 600 including five wireless power transmission systems 601 a-601 e each having a circular transmission range 615 a-615 e, respectively, and six wireless power receiver clients 603 a-603 f. The circular transmission ranges 615 a-615 e are shown for simplicity; actual transmission ranges can vary depending on the individual WPTS and the environment (e.g., based on changes in conditions, positioning of reflective objects, etc.). The transmission ranges indicate the distance to which wireless power can be delivery to a wireless power receiver client.

Wireless power transmission systems 601 a-601 e can be any wireless chargers such as, for example, wireless power transmission system 101 of FIG. 1, although alternative configurations are possible. Likewise, wireless power receiver clients 603 a-603 f can be wireless power receiver clients 103 of FIG. 1, although alternative configurations are possible. As discussed herein a wireless device (not shown), e.g., wireless device 102 of FIG. 1), can have one or more embedded, attached, and/or otherwise integrated wireless power receiver clients 603.

In the example of FIG. 6, each wireless power receiver client 603 a-f is within range of one or more wireless power transmission systems 601. The techniques described herein provide the wireless power receiver clients with techniques for selecting an optimal wireless power transmission system when wireless power receiver client is within range of more than one wireless power transmission system. In some embodiments, the optimal wireless power transmission system can be determined based on various selection criteria.

FIG. 7 is a flow diagram illustrating an example process 700 for establishing RF power connections with wireless power transmission systems in multi-wireless power transmission system environments, according to some embodiments. More specifically, FIG. 7 illustrates techniques for determining a wireless power transmission system with which to connect when the multiple wireless power transmission systems are within range. Components of a wireless power receiver client such as, for example, wireless power receiver client 103 of FIG. 1 or 400 of FIG. 4, can, among other functions, perform the example process 700.

To begin, at step 710, the wireless power receiver client receives an indication to enter a listen mode. In some embodiments, one or more timers may be set such that the listen mode occurs periodically for a pre-determined length of time. For example, the listen mode could occur for a length of one to two minutes every ten to sixty minutes. In some embodiments, the length of time of the listen mode can be set up as a multiple of the amount of time between broadcasts from a wireless power transmission system. For example, wireless power transmission systems may broadcast a connection invitation, e.g., a “join my network” message, at an interval of every twenty seconds. In such cases, the length of time for operating in the listen mode can be set to between 3×-6× the wireless power transmission system broadcast interval. Alternatively, or additionally, the wireless power receiver client can automatically go into the listen mode when the received power drops below a threshold, or drops below a set percentage from the previous power (e.g. if the received power drops 20% for 60 seconds, the client enters can be configured to enter the listen mode). At step 712, the wireless power receiver client optionally starts a listen mode timer and enters the listen mode.

At step 714, the wireless power receiver client listens for broadcast signals transmitted by wireless power transmission systems in wireless power delivery environment. The broadcast signals can include connection invitations and/or information signaling (e.g., ‘join my network’ messages). At decision step 716, if the wireless power receiver client determines whether a connection invitation and/or other connection information is received from a wireless power transmission system. If not, at decision step 730, the wireless power receiver client determines whether the listen mode timer has expired. If the listen mode timer has expired, the wireless power receiver client exits the listen mode operation and resumes normal operations (e.g., power reception) in a normal operating mode. However, if the listen mode time has not expired then the process continues again at step 714.

Again referring to step 716, if the wireless power receiver client receives a connection invitation and/or other connection information from a particular wireless power transmission system (WPTS) then, at step 718, the wireless power receiver client determines and/or otherwise identifies attributes of the WPTS. As discussed herein, determining attributes of the WPTS can include, by way of example and not limitation, measuring a signal strength or RSSI of the signal received from the WPTS, e.g., the connection invitation, identifying a number of other wireless power receiver clients associated with the first wireless power transmission system, etc. In this context, the wireless power receiver clients associated with the first wireless power transmission system are the wireless power receiver clients that have previously responded to the connection invitation. In some embodiments, the wireless power receiver client can determine the number of devices associated with the wireless power transmission system by, for example, receiving a message from the wireless power transmission system providing this information, by receiving unique beacon signals from other clients, etc.

At step 720, the wireless power receiver client accesses attributes of other wireless power transmission systems in the wireless power delivery environment. In some embodiments, the attributes of other wireless power transmission systems can be maintained in a wireless power ranking table. At step 722, accesses selection criteria for determining the ‘optimal’ wireless power transmission system with which to connect. The selection criteria can include techniques, algorithms, threshold, etc. that are utilized by the wireless power receiver client to score and/or rank the wireless power transmission systems within range. For example, the selection criteria can include signal strength threshold values, the number of wireless power receiver clients connected to a wireless power transmission system being above and/or below particular thresholds, etc. An example of various selection criteria is shown and discussed in greater detail with reference to example table 1000 of FIG. 10.

At decision step 726, the wireless power receiver client determines whether to accept the connection invitation from the WPTS. An example illustrating a process of determining whether to accept the connection invitation from the WPTS is shown and discussed in greater detail with reference to FIG. 8. If the connection invitation is accepted, then at step 728, the wireless power receiver client establishes a connection with the WPTS and the process subsequently continues at decision step 730. Alternatively, the process can resume normal operation after a connection with the WPTS is established. If the connection invitation is not accepted, then the process continues at decision step 730 without establishing a new connection.

FIG. 8 is a flow diagram illustrating an example process 800 for determining whether to accept a connection invitation from a WPTS, according to some embodiments. More specifically, FIG. 8 illustrates an example whereby wireless power transmission systems within range are scored and ranked to make a determination as to whether to accept a connection invitation received from a particular WPTS. Components of a wireless power receiver client such as, for example, wireless power receiver client 103 of FIG. 1 or 400 of FIG. 4, can, among other functions, perform the example process 800.

To begin, at step 810, the wireless power receiver client generates a score for the WPTS. An example illustrating generation of a score for a WPTS is shown and discussed in greater detail with reference to FIG. 9. At step 812, the wireless power receiver client accesses previously generated scores for the other wireless power transmission systems. As discussed herein, the attributes and/or scores and ranks for each wireless power transmission system within range can be kept and maintained by the wireless power receiver client.

At step 814, the wireless power receiver client ranks the wireless power transmissions systems based on the scores and, at decision step 816, the wireless power receiver client determines if the newly ranked wireless power transmission system (i.e., the wireless power transmission system which sent the invitation) is greater than the rank of the current highest ranking wireless power transmission system (assuming that there is at least one current wireless power transmission system ranking). If the newly ranked wireless power transmission system is higher than the current highest ranking wireless power transmission system, then the wireless power receiver client makes a determination to accept the connection invitation at step 818. Alternatively, if the newly ranked wireless power transmission system is not higher than the current highest ranking wireless power transmission system, then the wireless power receiver client makes a determination to not to accept the connection invitation at step 820.

FIG. 9 is a flow diagram illustrating an example process 900 of scoring wireless power transmission systems within range, according to some embodiments. As discussed herein the scores can be used to identify and/or otherwise determine the optimal wireless power transmission system with which to connect when a client is within range of multiple wireless power transmission systems. Components of a wireless power receiver client such as, for example, wireless power receiver client 103 of FIG. 1 or 400 of FIG. 4, can, among other functions, perform the example process 900.

To begin, at step 910, the wireless power receiver client measures the signal strength of the signal received from the wireless power transmission system. At process 912, the wireless power receiver client determines the number of devices associated with the wireless power transmission system, e.g. by receiving a message from the wireless power transmission system providing this information, or by receiving unique beacon signals from other clients. At process 914, the wireless power receiver client identifies client classification information. At process 916, the wireless power client optionally applies classification weights to the criteria. Lastly, at process 918, the wireless power receiver client ranks the wireless power transmission systems based on the weighted criteria.

FIG. 10 is an example table 1000 illustrating various wireless power transmission system selection criteria, according to some embodiments. Additional or fewer criteria are possible. As illustrated in the example of FIG. 10, in some embodiments, the criteria can have accompanying weights. As shown, a client may have a low power usage classification (e.g. a smoke alarm) and, thus, receive a low weight, while another may have a high classification (e.g. a laptop, or a laptop with less than 20% of remaining battery), and, thus, receive a high weight. Another criteria may be the number of devices. Thus, if a wireless power transmission system is already burdened with large number of devices, another wireless power transmission system may be selected.

FIG. 11 is a flow diagram illustrating another example process 1100 for establishing connections with continuous power delivery wireless charging systems, according to some embodiments. The steps of FIG. 11 are generally self-explanatory and, thus, not discussed in greater detail here. As discussed herein, the “Join network invitation” is a special broadcast message transmitted from a wireless power transmission system to one or more clients inviting the clients to join the wireless power transmission system's network. The decision step, “Is present invitation from preferred wireless power transmission system?” generally checks if the presently received invitation is from the network the client wants to join.

FIG. 12 depicts a block diagram illustrating example components of a representative mobile device or tablet computer 1200 with a wireless power receiver or client in the form of a mobile (or smart) phone or tablet computer device, according to some embodiments. Various interfaces and modules are shown with reference to FIG. 12, however, the mobile device or tablet computer does not require all of modules or functions for performing the functionality described herein. It is appreciated that, in many embodiments, various components are not included and/or necessary for operation of the category controller. For example, components such as GPS radios, cellular radios, and accelerometers may not be included in the controllers to reduce costs and/or complexity. Additionally, components such as ZigBee radios and RFID transceivers, along with antennas, can populate the Printed Circuit Board.

The wireless power receiver client can be a power receiver client 103 of FIG. 1, although alternative configurations are possible. Additionally, the wireless power receiver client can include one or more RF antennas for reception of power and/or data signals from a power transmission system, e.g., wireless power transmission system 101 of FIG. 1.

FIG. 13 depicts a diagrammatic representation of a machine, in the example form, of a computer system within which a set of instructions, for causing the machine to perform any one or more of the methodologies discussed herein, may be executed.

In the example of FIG. 13, the computer system includes a processor, memory, non-volatile memory, and an interface device. Various common components (e.g., cache memory) are omitted for illustrative simplicity. The computer system 1300 is intended to illustrate a hardware device on which any of the components depicted in the example of FIG. 1 (and any other components described in this specification) can be implemented. For example, the computer system can be any radiating object or antenna array system. The computer system can be of any applicable known or convenient type. The components of the computer system can be coupled together via a bus or through some other known or convenient device.

The processor may be, for example, a conventional microprocessor such as an Intel Pentium microprocessor or Motorola power PC microprocessor. One of skill in the relevant art will recognize that the terms “machine-readable (storage) medium” or “computer-readable (storage) medium” include any type of device that is accessible by the processor.

The memory is coupled to the processor by, for example, a bus. The memory can include, by way of example but not limitation, random access memory (RAM), such as dynamic RAM (DRAM) and static RAM (SRAM). The memory can be local, remote, or distributed.

The bus also couples the processor to the non-volatile memory and drive unit. The non-volatile memory is often a magnetic floppy or hard disk, a magnetic-optical disk, an optical disk, a read-only memory (ROM), such as a CD-ROM, EPROM, or EEPROM, a magnetic or optical card, or another form of storage for large amounts of data. Some of this data is often written, by a direct memory access process, into memory during execution of software in the computer 1300. The non-volatile storage can be local, remote, or distributed. The non-volatile memory is optional because systems can be created with all applicable data available in memory. A typical computer system will usually include at least a processor, memory, and a device (e.g., a bus) coupling the memory to the processor.

Software is typically stored in the non-volatile memory and/or the drive unit. Indeed, for large programs, it may not even be possible to store the entire program in the memory. Nevertheless, it should be understood that for software to run, if necessary, it is moved to a computer readable location appropriate for processing, and for illustrative purposes, that location is referred to as the memory in this paper. Even when software is moved to the memory for execution, the processor will typically make use of hardware registers to store values associated with the software, and local cache that, ideally, serves to speed up execution. As used herein, a software program is assumed to be stored at any known or convenient location (from non-volatile storage to hardware registers) when the software program is referred to as “implemented in a computer-readable medium”. A processor is considered to be “configured to execute a program” when at least one value associated with the program is stored in a register readable by the processor.

The bus also couples the processor to the network interface device. The interface can include one or more of a modem or network interface. It will be appreciated that a modem or network interface can be considered to be part of the computer system. The interface can include an analog modem, isdn modem, cable modem, token ring interface, satellite transmission interface (e.g. “direct PC”), or other interfaces for coupling a computer system to other computer systems. The interface can include one or more input and/or output devices. The I/O devices can include, by way of example but not limitation, a keyboard, a mouse or other pointing device, disk drives, printers, a scanner, and other input and/or output devices, including a display device. The display device can include, by way of example but not limitation, a cathode ray tube (CRT), liquid crystal display (LCD), or some other applicable known or convenient display device. For simplicity, it is assumed that controllers of any devices not depicted in the example of FIG. 13 reside in the interface.

In operation, the computer system 1300 can be controlled by operating system software that includes a file management system, such as a disk operating system. One example of operating system software with associated file management system software is the family of operating systems known as Windows® from Microsoft Corporation of Redmond, Wash., and their associated file management systems. Another example of operating system software with its associated file management system software is the Linux operating system and its associated file management system. The file management system is typically stored in the non-volatile memory and/or drive unit and causes the processor to execute the various acts required by the operating system to input and output data and to store data in the memory, including storing files on the non-volatile memory and/or drive unit.

Some portions of the detailed description may be presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, as apparent from the following discussion, it is appreciated that throughout the description, discussions utilizing terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized apparatus to perform the methods of some embodiments. The required structure for a variety of these systems will appear from the description below. In addition, the techniques are not described with reference to any particular programming language, and various embodiments may thus be implemented using a variety of programming languages.

In alternative embodiments, the machine operates as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine may operate in the capacity of a server or a client machine in a client-server network environment or as a peer machine in a peer-to-peer (or distributed) network environment.

The machine may be a server computer, a client computer, a personal computer (PC), a tablet PC, a laptop computer, a set-top box (STB), a personal digital assistant (PDA), a cellular telephone, an iPhone, a Blackberry, a processor, a telephone, a web appliance, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine.

While the machine-readable medium or machine-readable storage medium is shown in an exemplary embodiment to be a single medium, the term “machine-readable medium” and “machine-readable storage medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term “machine-readable medium” and “machine-readable storage medium” shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the presently disclosed technique and innovation.

In general, the routines executed to implement the embodiments of the disclosure, may be implemented as part of an operating system or a specific application, component, program, object, module or sequence of instructions referred to as “computer programs.” The computer programs typically comprise one or more instructions set at various times in various memory and storage devices in a computer, and that, when read and executed by one or more processing units or processors in a computer, cause the computer to perform operations to execute elements involving the various aspects of the disclosure.

Moreover, while embodiments have been described in the context of fully functioning computers and computer systems, those skilled in the art will appreciate that the various embodiments are capable of being distributed as a program product in a variety of forms, and that the disclosure applies equally regardless of the particular type of machine or computer-readable media used to actually effect the distribution.

Further examples of machine-readable storage media, machine-readable media, or computer-readable (storage) media include but are not limited to recordable type media such as volatile and non-volatile memory devices, floppy and other removable disks, hard disk drives, optical disks (e.g., Compact Disk Read-Only Memory (CD ROMS), Digital Versatile Disks, (DVDs), etc.), among others, and transmission type media such as digital and analog communication links.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof, means any connection or coupling, either direct or indirect, between two or more elements; the coupling of connection between the elements can be physical, logical, or a combination thereof. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or,” in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.

The above detailed description of embodiments of the disclosure is not intended to be exhaustive or to limit the teachings to the precise form disclosed above. While specific embodiments of, and examples for, the disclosure are described above for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative embodiments may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative or subcombinations. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are, at times, shown as being performed in a series, these processes or blocks may instead be performed in parallel, or may be performed at different times. Further, any specific numbers noted herein are only examples: alternative implementations may employ differing values or ranges.

The teachings of the disclosure provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments.

Any patents and applications and other references noted above, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the disclosure can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the disclosure.

These and other changes can be made to the disclosure in light of the above Detailed Description. While the above description describes certain embodiments of the disclosure, and describes the best mode contemplated, no matter how detailed the above appears in text, the teachings can be practiced in many ways. Details of the system may vary considerably in its implementation details, while still being encompassed by the subject matter disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the disclosure should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the disclosure with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the disclosure to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the disclosure encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the disclosure under the claims.

While certain aspects of the disclosure are presented below in certain claim forms, the inventors contemplate the various aspects of the disclosure in any number of claim forms. For example, while only one aspect of the disclosure is recited as a means-plus-function claim under 35 U.S.C. § 112, ¶16, other aspects may likewise be embodied as a means-plus-function claim, or in other forms, such as being embodied in a computer-readable medium. (Any claims intended to be treated under 35 U.S.C. § 112, ¶16 will begin with the words “means for”.) Accordingly, the applicant reserves the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the disclosure.

The detailed description provided herein may be applied to other systems, not necessarily only the system described above. The elements and acts of the various examples described above can be combined to provide further implementations of the invention. Some alternative implementations of the invention may include not only additional elements to those implementations noted above, but also may include fewer elements. These and other changes can be made to the invention in light of the above Detailed Description. While the above description defines certain examples of the invention, and describes the best mode contemplated, no matter how detailed the above appears in text, the invention can be practiced in many ways. Details of the system may vary considerably in its specific implementation, while still being encompassed by the invention disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific examples disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the invention. 

What is claimed is:
 1. A wireless power receiver apparatus comprising: means for entering a listening mode to actively listen for connection invitations broadcast by wireless power transmission systems in a wireless power delivery environment, the wireless power transmission systems each including multiple antennas configured to transmit coherent wireless power signals for delivery to wireless power receiver apparatuses; means for receiving, during the listening mode, the connection invitations; means for processing the connection invitations to identify attributes associated with the wireless power transmission systems; means for generating or updating one or more scores associated with the wireless power transmission systems based on the corresponding attributes; and means for establishing a connection with at least one of the wireless power transmission systems based on the generated or updated one or more scores.
 2. The wireless power receiver apparatus of claim 1, wherein the means for generating or updating the one or more scores associated with the wireless power transmission systems further comprise: means for identifying a client classification associated with a wireless device in which the wireless power receiver apparatus is embedded, the client classification identifying one or more classification weights associated with the attributes; and means for applying the classification weights to the attributes.
 3. The wireless power receiver apparatus of claim 1, further comprising: means for accessing scores associated with other wireless power transmission systems in the wireless power delivery environment; and means for ranking the wireless power transmission systems according to the corresponding scores.
 4. The wireless power receiver apparatus of claim 3, further comprising: means for making a determination to accept at least one connection invitation associated with the at least one wireless power transmission system based on the ranking of the wireless power transmission systems.
 5. The wireless power receiver apparatus of claim 1, wherein the means for processing the connection invitations to identify attributes associated with the wireless power transmission systems further comprises: means for measuring signal strengths of the connection invitations.
 6. The wireless power receiver apparatus of claim 1, wherein the means for processing the connection invitations to identify attributes associated with the wireless power transmission systems further comprises: means for identifying a number of other wireless power receiver clients associated with the first wireless power transmission system.
 7. The wireless power receiver apparatus of claim 1, further comprising: means for, prior to receiving the connection invitation, receiving an indication to enter an invitation listen mode and responsively entering the listen mode and commencing a listen mode timer.
 8. The wireless power receiver apparatus of claim 1, wherein the connection invitations are broadcast periodically by one or more of the wireless power transmission systems for reception by wireless power receiver apparatuses in the wireless power delivery environment.
 9. The wireless power receiver apparatus of claim 1, wherein the means entering the listening mode further comprise: directing one or more antennas of the wireless power receiver apparatus or a wireless device in which the wireless power receiver apparatus is embedded to listen for the connection invitations broadcast by the wireless power transmission systems.
 10. The wireless power receiver apparatus of claim 1, further comprising: means for directing one or more transceivers of the wireless power receiver apparatus or a wireless device in which the wireless power receiver apparatus is embedded to transmit a response to at least one of the connection invitations that indicates an acceptance of the connection invitation.
 11. A computer readable storage medium having program instructions stored thereon which, when executed by one or more processors of a wireless power receiver apparatus, cause the wireless power receiver apparatus to: during listening mode, process connection invitations broadcast by wireless power transmission systems in a wireless power delivery environment to identify attributes associated with the wireless power transmission systems, wherein the wireless power transmission systems each include multiple antennas configured to transmit coherent wireless power signals for delivery to wireless power receiver apparatuses; generate or update one or more scores associated with the wireless power transmission systems based on the corresponding attributes; and establish a connection with at least one of the wireless power transmission systems based on the generated or updated one or more scores.
 12. The computer readable storage medium of claim 11, wherein the instructions, when executed by the one or more processors, further cause the wireless power receiver apparatus to: access scores associated with other wireless power transmission systems in the wireless power delivery environment; and rank the wireless power transmission systems according to the corresponding scores.
 13. The computer readable storage medium of claim 12, wherein to generate or update the one or more scores, the instructions, when executed by the one or more processors, further cause the wireless power receiver apparatus to: identify a client classification associated with a wireless device in which the wireless power receiver apparatus is embedded, wherein the client classification identifies one or more classification weights associated with the attributes; and apply the classification weights to the attributes.
 14. The computer readable storage medium of claim 12, wherein the instructions, when executed by the one or more processors, further cause the wireless power receiver apparatus to: accept at least one connection invitation associated with the at least one wireless power transmission system based on the ranking of the wireless power transmission systems.
 15. The computer readable storage medium of claim 11, wherein to process the connection invitations to identify attributes associated with the wireless power transmission systems, the instructions, when executed by the one or more processors, further cause the wireless power receiver apparatus to: measure signal strengths of the connection invitations.
 16. The computer readable storage medium of claim 11, wherein the instructions, when executed by the one or more processors, further cause the wireless power receiver apparatus to: directing one or more transceivers of the wireless power receiver apparatus or a wireless device in which the wireless power receiver apparatus is embedded to transmit a response to the at least one of the connection invitations that indicates an acceptance of the connection invitation message.
 17. A wireless power receiver apparatus comprising: one or more radio frequency (RF) transceivers; control circuitry configured to direct the one or more RF transceivers to establish a connection with at least one wireless power transmission system of multiple wireless power transmission systems in a wireless power delivery environment, the control circuitry including: listen mode reception logic configured to receive, via the one or more RF transceivers, connection invitations and responsive process the connection invitations to identify attributes associated with the multiple wireless power transmission systems; wireless power transmission selection logic configured to generate or update one or more scores associated with the wireless power transmission systems based on the corresponding attributes; and connection establishing logic configured to establish the connection with the at least one wireless power transmission system based on the generated or updated one or more scores. 